Comedian Jimmy Carr is considering further action against Jim Davidson, whom he claims stole one of his jokes.
Jimmy Carr hosted Channel 4's Distraction
Carr wrote to Davidson demanding an apology after he allegedly repeated Carr's joke about an overweight woman.
Carr was not satisfied with Davidson's response and was consulting lawyers on further legal action, his agent Hannah Chambers told BBC News Online.
But Davidson's agent has dismissed the claims as "madness", saying any similarity is a coincidence.
Carr told the disputed joke during a Royal Variety Performance in 2002. A similar quip was repeated by Davidson on his BBC1 show Jim Davidson On the Road.
The joke runs: "Someone came up to me last week and complained about a joke, quite a big-boned girl.
She said: "I think you're fattist." I said: "No, I think you're fattest".
Ms Chambers said she and Carr took issue with Davidson because: "It's not acceptable and it doesn't happen a lot."
But Davidson's agent and manager Laurie Mansfield dismissed the row as a 'storm in a teacup' over one line in a 50-minute routine.
He told BBC News Online: "This is madness.
"He didn't deliberately steal that joke thinking 'I'm going to sit on that for 18 months, and then use it in a TV show'.
"It's been around for ages. It's very hard to copyright any joke at all.
"We wrote back and apologised. We are both fans of Jimmy Carr, we are sorry if it has offended him."
He said Davidson was "upset and disappointed" Carr felt as he did and any similarity was "coincidental, not deliberate".
A BBC spokeswoman confirmed that a letter had been received from Jimmy Carr.
It was for Jim Davidson to respond and the BBC had no obligation to take further action, she said.